Lakes are a vital part of the ecosystem. They serve many uses, and some have the freshest available water on Earth (the majority of freshwater is secured in the Antarctic as groundwater). The marine organisms that inhabit the body of water are also very important. They keep the food chain running, and if that were to break, it would cause a serious threat. Unfortunately, lakes are getting contaminated and marine life is slowly getting jeopardized. When it rains, the excess water on the ground doesn’t stay put, it moves according to gravity. Some of it can replenish the groundwater, but most of it becomes runoff. Runoff is important as it keeps lakes full of water and can also have the strength to alter the terrain using erosion.However, runoff can have its downsides too. Sediment (loose slit that sits on the bottom of lakes, streams, and rivers.) is so contaminated is because of all the vast amount of industrial manufacturing buildings built around watersheds (land that drains into lakes, rivers, and streams that carry the water out into the ocean as well.) over the years. They pollute the area around them, and the runoff can sweep it away into the lakes, which then exert toxins and pollutants into the water. There are many examples of how negative these effects can be. One of the main reasons why sediment is hazardous is because of the danger it puts marine life in. Marine animals can collect toxins when consuming their food in the mud. The predators that eat them can be attacked by the previous toxins in their prey. This repeats as the pollutants carefully make their way up and up to the top of the food chain, in more higher concentrations. The birds who eat fish can also get affected by the toxins, causing abundant reproductive rates. Humans may possibly get infected too, so fish can be risky to eat in certain places where toxic levels are high. Sediment can also clog fish gills (preventing reproduction, growth, and strength when fighting diseases), increase the cost of available drinking water, create murky water (preventing vegetation, and the ability for animals to search for their food), and transport nutrients that produce blue-green algae (blue-green algae set toxins free into the water, which can make swimmers ill).